AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Neutralization of Electrosprayed Particles via Photo-ionizer
QIAOLING LIU, Da-Ren Chen, Washington University in St. Louis
Abstract Number: 236 Working Group: Instrumentation and Methods
Abstract Because of the capability of producing monodisperse particles when operated at the cone-jet mode, electrospray technology has been widely proposed to apply in many areas such as nano-material synthesis, drug delivery, particle encapsulation and thin film/particle film deposition. Particles generated from electrospray are highly charged and easily deposited on walls due to the electrostatic effect. Charge reduction is often the necessity to keep the particles airborne for transportation. Reduction of charges on electrosprayed particles has been done via either radioactive or AC-corona-based neutralizers. To ensure the minimal charges on particles AC-corona-based neutralizers require the careful monitoring of balanced bipolar ions. At the same time, tight safety regulation limits the use of radioactive material as neutralizers. It is thus needed to search for an alternative to generate bipolar ions for the charge reduction of electrosprayed particles. In this study we investigated the photoionizer (i.e., a soft X-ray source) as an alternative to neutralize electrosprayed particles. For this investigation we had designed a single-capillary electrospray aerosol generator with the charge reduction chamber in which the photoionizer was used as the bi-polar ion source. To evaluate the performance of the particle neutralization in the above-described generator, a custom-made scanning mobility particle sizer (SMPS), in which the polarity of high voltage power supply can be switched, was used to measure the size and charge distributions of electrosprayed particles exiting from the generator. The fluorescence particle method was also applied to quantify the fractions of neutral and positively/negatively charged particles exiting from the generator. We further investigated the effect of photoionizer’s intensity and position on the spray current when electrospray was operated at various spray modes. The detail of this study will be presented in this talk.